Person: Negredo Moreno, Ana María
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First Name
Ana María
Last Name
Negredo Moreno
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física de la Tierra y Astrofísica
Area
Física de la Tierra
Identifiers
10 results
Search Results
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Item The topography of the Iberian Peninsula from integrated geophysical-petrological multi-data inversion(Physics of the Earth and Planetary Interiors, 2021) Fullea Urchulutegui, Javier; Negredo Moreno, Ana María; Charco, María; Palomeras, Imma; Afonso, Juan Carlos; Villaseñor, AntonioThe topography of the Iberian Peninsula is characterized by the presence of Variscan and Alpine orogenic belts and foreland basins, but what sets it apart from the rest of Western Europe are the large elevated flat surfaces (700 m above sea-level on average) in its central parts. The origin and support of such high average topography, whether isostatic or dynamic in nature, is a matter of intense debate. To understand Iberian topography, it is key to have a reliable image of the present-day lithospheric thermochemical structure. So far, this structure remains poorly constrained, particularly at mantle level. The goal of this paper is to derive robust estimates of the thermal, compositional and density structure of the lithosphere beneath the Iberian Peninsula from an integrated geophysical-petrological proba-bilistic inversion of surface wave, elevation, geoid anomaly and heat flow data. Our inversion reveals an average lithospheric thickness of 80-100 km in the Iberian Peninsula with only moderate lateral variations. The most prominent lithospheric thickness change is a steep decrease from the central to the easternmost Pyrenees. The thinnest lithosphere in our models is found below the south-eastern Mediterranean margin (<80 km), overlapping with the Neogene Tallante-Cabo de Gata volcanic fields. The present-day thermochemical structure reveals a clear imprint of the geodynamic evolution of Iberia. Lithospheric thickness and, therefore, lithospheric geotherms are to a large extent related to Alpine Cenozoic compression and extension. The western Pyrenees and Iberian chains seem to have been affected by Mesozoic rifting processes that imprinted a fertile signature into the originally more refractory Variscan Iberian lithosphere. In the Betic domain to the south, the lithospheric thermochemical structure is likely conditioned by the ongoing Alboran subduction. Except for the Mediterranean margin, where we find evidence for moderate negative dynamic topography, most of the surface elevation in Iberia can be explained by lateral density contrasts associated with variations in crustal and lithospheric thickness and lithology.Item The Gibraltar slab dynamics and its influence on past and present-day Alboran domain deformation: Insights from thermo-mechanical numerical modelling(Frontiers in Earth Science, 2023) Gea, Pedro J.; Negredo Moreno, Ana María; Mancilla, Flor de LisThe origin and tectonic evolution of the Gibraltar Arc system is the result of a complex geodynamic evolution involving the convergence of the Eurasian and African plates and the dynamic impact of the Gibraltar slab. Although geologic and geophysical data collected in the last few years have increased our knowledge of the Gibraltar Arc region, it is still unclear which are the mechanical links between the Gibraltar slab and the past deformation of the overriding Alboran lithosphere, as well as to which degree this subduction system is presently active. In this study, we use 2D numerical modelling to investigate the impact of the Gibraltar slab dynamics on the deformation of the overriding Alboran lithosphere. Our model simulates a WE generic vertical section at an approximate latitude of 36 degrees N and considers an initial setup at about Burdigalian times (similar to 20 Ma), when the subduction front position is relatively well constrained by recent tectonic reconstructions. Our modelling shows a switch in the overriding plate (OP) stress state from extensional stresses during the slab rollback to compressional stresses near the trench when the rollback velocity decreases, caused by the change in slab-induced mantle flow. We also find that much of the crustal and lithospheric deformation occur during fast slab rollback and OP extension in the first 10 Myr of evolution, while after that only moderate deformation associated with subduction is predicted. Finally, we find that despite the subduction rollback ceases, the ongoing motion of the deeper portion of the slab induces a mantle flow that causes some amount of west-directed basal drag of the Alboran lithosphere. This basal drag generates interplate compresional stresses compatible with the distribution of intermediate-depth earthquakes in western Alboran.Item Geodynamic modeling of edge-delamination driven by subduction-transform edge propagator faults: the Westernmost Mediterranean Margin (Central Betic Orogen) Case Study(Frontiers in Earth Science, 2020) Negredo Moreno, Ana María; Mancilla, F. de L.; Clemente, C.; Morales, J.; Fullea Urchulutegui, JavierLithospheric tearing at slab edges is common in scenarios where retreating slabs face continental margins. Such tearing is often accommodated via subvertical STEP (SubductionTransform Edge Propagator) faults that cut across the entire lithosphere and can result in sharp lateral thermal and rheological variations across the juxtaposed lithospheres. This setting favors the occurrence of continental delamination, i.e., the detachment between the crust and the lithospheric mantle. In order to evaluate this hypothesis, we have chosen a wellstudied natural example recently imaged with unprecedented seismic resolution: the STEP fault under the central Betic orogen, at the northern edge of the Gibraltar Arc subduction system (westernmost Mediterranean Sea). The Gibraltar Arc subduction is the result of the fast westward roll-back of the Alboran slab and it is in its last evolutionary stage, where the oceanic lithosphere has been fully consumed and the continental lithosphere attached to it collides with the overriding plate. In this study we investigate by means of thermo-mechanical modeling the conditions for, and consequences of, delamination post-dating slab tearing in the central Betics. We consider a setup based on a STEP fault separating the orogenic Betic lithosphere and the adjacent thinned lithosphere of the overriding Alboran domain. Our model analysis indicates that delamination is very sensitive to the initial thermal and rheological conditions, transitioning from a stable to a very unstable and rapidly evolving regime. We find two clearly differentiated regimes according to the time at which the process becomes unstable: fast and slow delamination. Although the final state reached in both the fast and slow regimes is similar, the dynamic surface topography evolution is dramatically different. We suggest that given a weak enough Iberian lower crust the delaminating lithospheric mantle peels off the crust and adopts a geometry consistent with the imaged southward dipping Iberian lithosphere in the central Betics. The lack of spatial correspondence between the highest topography and the thickest crust, as well as the observed pattern of uplift/ subsidence are properly reproduced by a model where relatively fast delamination (Reference Model) develops after slab tearing.Item Geophysical-petrological model for bidirectional mantle delamination of the Adria microplate beneath the northern Apennines and Dinarides orogenic systems(Journal of Geophysical Research: Solid Earth, 2022) Zhang, Wentao; Jiménez Munt, Ivone; Torne, Montserrat; Vergés, Jaume; Bravo Gutiérrez, Estefanía; Negredo Moreno, Ana María; Carminati, Eugenio; García Castellanos, Daniel; Fernàndez, ManelThis study presents a geophysical-geochemical integrated model of the thermochemical structure of the lithosphere and uppermost mantle along a transect from the Northern Tyrrhenian Sea to the Pannonian Basin, crossing the northern Apennines, the Adriatic Sea, and the Dinarides fold-thrust belt. The objectives are to image crustal thickness variations and characterize the different mantle domains. In addition, we evaluate the topographic response of opposed subductions along this transect and discuss their implications in the evolution of the region. Results show a more complex structure and slightly higher average crustal density of Adria compared to Tisza microplate. Below the Tyrrhenian Sea and Western Apennines, Moho lays at <25 km depth while along the Eastern Apennines it is as deep as 55 km. The modeled lithosphere-asthenosphere boundary (LAB) below the Tyrrhenian Sea and Pannonian Basin is flat lying at ∼75 and 90 km, respectively. Below the External Apennines and Dinarides the LAB deepens to 150 km, slightly shallowing toward the Adriatic foreland basin at 125 km depth. Our results are consistent with the presence of two mantle wedges, resulting from the rollback of the Ligurian-Tethys and Vardar-NeoTethys oceanic slabs followed by continental mantle delamination of the eastern and western distal margins of Adria. These two opposed slabs beneath the Apennines and Dinarides are modeled as two thermal sublithospheric anomalies of −200°C. Most of the elevation along the profile is under thermal isostasy and departures can be explained by regional isostasy with an elastic thickness between 10 and 20 km.Item On the origin of the Canary Islands: Insights from mantle convection modelling(Earth and Planetary Science Letters, 2022) Negredo Moreno, Ana María; van Hunen, Jeroen; Rodríguez González, Juan Tinguaro; Fullea Urchulutegui, JavierThe Canary Islands hotspot consists of seven volcanic islands, mainly of Neogene age, rooted on oceanic Jurassic lithosphere. Its complex structure and geodynamic setting have led to different hypotheses about its origin and evolution, which is still a matter of a vivid debate. In addition to the classic mantle plume hypothesis, a mechanism of small-scale mantle convection at the edge of cratons (Edge Driven Convection, EDC) has been proposed due to the close proximity of the archipelago to the NW edge of the NW African Craton. A combination of mantle plume upwelling and EDC has also been hypothesized. In this study we evaluate these hypotheses quantitatively by means of numerical two-dimensional thermo-mechanical models. We find that models assuming only EDC require sharp edges of the craton and predict too narrow areas of partial melting. Models where the ascent of an upper-mantle plume is forced result in an asymmetric mantle flow pattern due to the interplay between the plume and the strongly heterogeneous lithosphere. The resulting thermal anomaly in the asthenosphere migrates laterally, in agreement with the overall westward decrease of the age of the islands. We suggest that laterally moving plumes related to strong lithospheric heterogeneities could explain the observed discrepancies between geochronologically estimated hotspot rates and plate velocities for many hotspots.Item Advances in the modeling of the Iberian thermal lithosphere and perspectives on deep geothermal studies(Geothermal energy, 2023) Torne, M.; Jiménez Munt, I.; Negredo Moreno, Ana María; Fullea Urchulutegui, Javier; Vergés, J.; Marzán, I.; Alcalde, J.; Gómez Rivas, E.; García de la Noceda, C.Renewable energy sources are key to achieve the transition toward clean energy system. Among them, the geothermal energy has a production whose efectiveness requires sufcient understanding of the temperature distribution and fuid circulation at depth, as well as of the lithological and petrophysical properties of the crust. The focus of this paper is twofold: frst, we summarize the main advances in the develop ment of new methodologies and numerical codes to characterize the properties of the thermal lithosphere in terms of its, temperature, density and composition; second, based on the compilation of available thermal modelling results, we present the depth of the thermal Lithosphere–Asthenosphere Boundary (LAB) of the Iberian Peninsula and the temperature distribution at crustal depths of 5, 10, and 20 km, in addition to at Moho level. At 5 km depth, the temperature is above 110 °C with local anomalies (>130 °C) located in the Iberian Massif and Cenozoic volcanic provinces. A similar pattern is observed at 10 and 20 km depth, where temperatures are above 190 °C and 350 °C, respectively. At 20 km depth, anomalies above>500 °C, delineate the SE and NE Cenozoic volcanic provinces. At Moho depths, temperature ranges from 450 to 800 °C with hot regions mainly located along the Iberian Massif and the SE and NE volcanic provinces. The compiled results do not show any lithospheric anomaly that could give rise to high temperatures at shallow depths, but they do show an acceptable exploi tation potential at intermediate depths. With regard to the direct use of district and greenhouse heating and for industrial processes, the potential is great throughout the Peninsula, the main challenges being the availability of groundwater and drilling costs.- Project number: 44
Item Geofísica-SMART: Simples experiMentos de enseñanza apRendizaje en entoRnos digiTales(2022) Martín Hernández, Fátima; Ledo Fernandez, Juan José; Negredo Moreno, Ana María; Pavón Carrasco, Francisco Javier; Fullea Urchulutegui, Javier; Osete López, María Luisa; Ruiz Martínez, Vicente Carlos; Arquero Campuzano, Saioa; Llanes Estrada, María Pilar; Druet Vélez, María; Valles-Iriso, Javier; Gómez-Paccard, Miriam; Bonilla Alba, Raquel; Rivera Pérez, Pablo; López Sánchez, CarolinaLa Geofísica es una disciplina asociada a la Física experimental con gran desarrollo en multitud de ámbitos que van desde la arqueología a diferentes areas de la ingeniería como la geotécnia, ingeniería de minas o ingeniería geológica o bien el ámbito académico. Precisa de un conocimiento Físico de las leyes de la naturaleza pero también una destreza asociada a la Física más aplicada con multitud de experimentos en campo. Éstos son a veces difíciles de encontrar en libros de texto que se centran en los aspectos teóricos de la disciplina. Por eso, este proyecto pretende hacer ver a los estudiantes el diseño, desarrollo y procesado de experiencias de Geofísica Aplicada o prospectiva dentro de su desarrollo curricular. Item The Mechanical Nature of the Lithosphere Beneath the Eastern Central Atlantic Hotspots(Geochemistry, Geophysics, Geosystems, 2023) Jiménez Díaz, Alberto; Negredo Moreno, Ana María; Kirby, John F.; Sánchez Pastor, Pilar; Fullea Urchulutegui, Javier; Ruiz Pérez, Javier; Pérez Gussinyé, Marta; Yu, ChuanhaiThe Eastern Central Atlantic (ECA) region includes the Azores, Canary, Cape Verde, Great Meteor, and Madeira hotspots. These hotspots exhibit a large variety of characteristics and are rooted in the lithosphere ranging in age from newly created at the Mid Atlantic Ridge to Jurassic at the NW Africa Atlantic margin. Therefore, the ECA region represents an excellent scenario to investigate in an integrated way the effects of hotspots on the mechanical structure of oceanic lithosphere. Here, we calculate the effective elastic thickness (Te) of the lithosphere from an analysis of gravity and topography. Azores hotspot is characterized by a Te < 10 km, whereas the Great Meteor, Cape Verde, and Madeira hotspots have intermediate Te (15–30 km) values. In contrast, the Canary hotspot is characterized by a much higher Te (>50 km), forming the largest and most prominent mechanical feature in the ECA. All the hotspots except Canary show standard elastic thickness values when compared to average values for the same age lithosphere and to other oceanic areas in the world. The high strength of the Canary hotspot may be related to the highly depleted mantle composition in the area. The comparison between the elastic thickness distribution and the upper mantle seismic velocity structure shows no correlation between the Te estimated at the ECA hotspots (with the exception of Azores) and the presence of low shear-wave velocity anomalies in the underlying mantle. This lack of correlation suggests a negligible effect of upper mantle temperature anomalies on the flexure of the ECA region.- Project number: PIMCD244/23-24
Item Cambiando el rol del profesorado en el aula de transmisor a facilitador(2024) De La Cámara Illescas, Álvaro; Calvo Fernández, Natalia; Ábalos Álvarez, Marta; Durán Montejano, Luis; García Herrera, Ricardo Francisco; González Rouco, Jesús Fidel; Losada Doval, Teresa; Montoya Redondo, María Luisa; Negredo Moreno, Ana María; Pavón Carrasco, Francisco Javier; Polo Sánchez, Irene; Rodríguez De Fonseca, María Belén; Sastre Marugán, Mariano; Yagüe Anguis, Carlos; Zurita Gotor, Pablo; De La Cámara Illescas, ÁlvaroEste proyecto propone un cambio del rol del docente en el aula de transmisor a facilitador. Para ello, se apuesta por implantar metodologías que favorezcan el aprendizaje cooperativo en el aula y potencien el desarrollo de competencias transversales. Item Time-scales of inter-eruptive volcano uplift signals: Three Sisters volcanic center, Oregon (United States)(Frontiers in Earth Science, 2021) Rodríguez Molina, Sara; González, Pablo J.; Charco Romero, María; Negredo Moreno, Ana María; Schmidt, David A.A classical inflation-eruption-deflation cycle of a volcano is useful to conceptualize the timeevolving deformation of volcanic systems. Such a model predicts accelerated uplift during pre-eruptive periods, followed by subsidence during the co-eruptive stage. Some volcanoes show puzzling persistent uplift signals with minor or no other geophysical or geochemical variations, which are difficult to interpret. Such temporal behaviors are usually observed in large calderas (e.g., Yellowstone, Long Valley, Campi Flegrei, Rabaul), but less commonly for stratovolcanoes. Volcano deformation needs to be better understood during inter-eruptive stages, to assess its value as a tool for forecasting eruptions and to understand the processes governing the unrest behavior. Here, we analyze intereruptive uplift signals at Three Sisters, a complex stratovolcano in Oregon (United States), which in recent decades shows persistent inter-eruptive uplift signals without associated eruptive activity. Using a Bayesian inversion method, we re-assessed the source characteristics (magmatic system geometry and location) and its uncertainties. Furthermore, we evaluate the most recent evolution of the surface deformation signals combining both GPS and InSAR data through a new non-subjective linear regularization inversion procedure to estimate the 26 years-long time-series. Our results constrain the onset of the Three Sisters volcano inflation to be between October 1998 and August 1999. In the absence of new magmatic inputs, we estimate a continuous uplift signal, at diminishing but detectable rates, to last for few decades. The observed uplift decay observed at Three Sisters is consistent with a viscoelastic response of the crust, with viscosity of ∼10^(18) Pa s around a magmatic source with a pressure change which increases in finite time to a constant value. Finally, we compare Three Sisters volcano time series with historical uplift at different volcanic systems. Proper modeling of scaled inflation time series indicates a unique and well-defined exponential decay in temporal behavior. Such evidence supports that this common temporal evolution of uplift rates could be a potential indicator of a rather reduced set of physical processes behind inter-eruptive uplift signals.